<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      div:nth-child(1) {
        margin: 0 auto;
        width: 100px;
        height: 30px;
        box-shadow: 1px 0px 5px 0px black;
      }
    </style>
  </head>
  <body>
    <div></div>
  </body>
</html>
